Unilateral agenesis of the facial artery with compensation by a giant transverse facial artery.

During routine dissections carried out in the course of our medical gross anatomy work, an unusual structure was found unilaterally on the left side of an adult male cadaver. Upon investigation, this was determined to be a hugely dilated transverse facial artery. Also noted was the complete absence of the ipsilateral facial artery. To our knowledge, this is the first report of complete agenesis and not simply diminution of the facial artery with compensatory enlargement of the transverse facial artery.